Amino acids secretion patterns with different operation strategies in 7 L fermentor when exogenously adding acetate.

(A) ABE fermentation by C. acetobutylicum (control, case #a). (B) ABE fermentation by C. acetobutylicum with exogenous acetate addition (4.0 g/L-broth). (C) ABE fermentation by co-culturing C. acetobutylicum/S. cerevisiae (0.20 g-DCW/L-broth) in coupling with exogenous acetate addition (4.0 g/L-broth). (D) ABE fermentation by co-culturing C. acetobutylicum/S. cerevisiae (0.20 g-DCW/L-broth) in coupling with exogenously adding acetate fermentation supernatant (acetic acid fermentation broth, acetate concentration 75 g/L, pure acetate adding amount of 8.0 g/L-broth).Black: lysine; white: methionine; horizontal shadow: phenylalanine; slashed shadow: tyrosine. (EPS)